1. Field of the Invention
The field of the invention is that of a Network in which Electronic Resources are shared among such a system's community of users. A Network is a distributed communicating system of computers which are interconnected by various electronic communication links and computer software protocols. Electronic Resources are (a) documents, files and/or other information sources which are accessible on a Network to its user community, or (b) references to and/or means of accessing such documents, files and/or information sources. The invention relates to a system for denoting (naming) the Electronic Resources of a Network and a related system for the fulfillment of requests for and/or execution of delivery of these Electronic Resources to users of the Network's user community.
2. Description of the Related Technology
A particularly well-known Network is the international information infrastructure, commonly called the Internet. The Internet is a world-wide Network whose Electronic Resources include (but are not limited to) text files, graphic files in various formats, World Wide Web "pages" in HTML (HyperText Mark-Up Language) format, files in various and arbitrary binary formats, and electronic mail addresses. As in many other Networks, the scheme for denotation of an Electronic Resource on the Internet is an "electronic address" which uniquely identifies its location within the network and within the computer in which it resides. On the Internet, for example, such an electronic address is called a Universal Resource Locator or URL, and consists of a specially formatted concatenation of information about the type of protocol needed to access the resource, a Network Domain identifier, identification of the particular computer on which the Electronic Resource is located, a port number, directory path information within the computer's file structure, and the file name of the resource.
Internet URLs and similar denotation schemes for Electronic Resources are cumbersome for human users. URLs are often more than 50 characters long and contain information which is neither interesting nor meaningful to seekers of information. For example, the NASA Internet web "homepage" has the URL "http://hypatia.gsfe.nasa.gov/NASA.sub.-- homepage.html."
The National Information Control (NIC) registers unique Internet domain names on a first come first served basis. Even if an entity can acquire a domain name which is mnemonic and easy to remember, the URLs associated with that domain may still be complex non-intuitive character sequences. Sometimes an entity cannot register a desired domain name because another entity has already registered that domain name with the NIC. The entity must then choose an alternate domain name, which often results in difficulty in finding that entity's Electronic Resources on the Internet. Additionally, due to length, software, and practicality considerations, domain names are often peculiar abbreviations, presenting additional confusion in locating an entity's Electronic Resources on the Internet. Furthermore, many entities do not possess their own computing equipment nor domain names, and must maintain their Electronic Resources in the domains of other entities, as in this example of a URL: "http://draco.centerline.com:8080/ franl/crypto.html," which denotes a web page on privacy and cryptography.
Thus, several difficulties face users attempting to locate Electronic Resources on a Network with a denotation system such as that in use on the Internet. They include the length, complexity and non-intuitive nature of denotations (URLs on the Internet), the need to type them correctly, and the difficulty in learning of the existence of the Electronic Resource and in discovering its correct denotation or URL.
Various software tools to facilitate the search for URLs have been proposed or developed for use on the Internet. These include "Yellow Pages," "White Pages," and "Web Crawlers." They all deal with compiling and maintaining classification systems of Electronic Resources on a Network. They all attempt to create and/or maintain a utility which presents an indexing scheme to a user so that he/she may learn of the existence of an Electronic Resource and retrieve its electronic address (or URL). "Yellow Page" indexes classify Electronic Resources by a hierarchy of subject areas in a manner similar to the telephone "yellow pages" or a library classification scheme. "White Page" indexes classify Electronic Resources by owner or name of the resource. These schemes inherit all the difficulties of classifying potentially huge name spaces, including the difficulties arising from overlapping and non-hierarchical subject areas and overlapping name spaces.
The Yellow Page approach suffers from the phenomenon of overlapping subject areas which occurs in any classification scheme. This can be illustrated by the difficulty of deciding whether to place "educational psychology" under "education" or "psychology" and that of classifying a document on Democracy and Fascism in Spain under possibly disparate subject areas of "democracy" or "fascism" or "Spanish history" in a classification scheme. These difficulties are well known in Library Science. The White Page approach is to classify by provider or owner. This is an excellent scheme providing that the information seeker knows the name(s) of potential providers of Electronic Resources. Neither of these schemes address the problem of complexity of the denotation of Electronic Resources. In some cases, the denotation need not be seen or dealt with by the user, as in the case of hypertext links ("hot links") within Internet Web pages. Web software automatically retrieves documents referred to in other documents without user intervention or entry of URLs. Web software ("browsers") also are able to retain URLs of Web pages in a user-created (usually hierarchical) classification scheme, and list these by page titles. This capability allows users to revisit (retrieve at a later time) web pages previously retrieved, as they may have changed.
Web crawlers and other search engines attempt to create indexes of the yellow or white page variety, together with their attendant classification scheme, by continually traversing Electronic Resources in a Network and compiling information about the resources encountered. In an environment similar to the World Wide Web in which documents link to other documents, search engines are able to extract the links from documents in order to extend their search to other documents. Various means are used to extrapolate subject areas and other classification schemes, ranging from author-provided keyword or indexing information through expert system techniques for ferreting index information from textual context. These engines participate in the construction apparatus for indexes such as yellow or white pages.
Some Networks include protocols such as the Internet "Finger" for finding an electronic mail address of a person. These protocols and their attendant software have the drawback of being unable to search a very large e-mail address space, and thus require additional information for their search, such as a Domain Name in the Internet. Other Internet protocols such as "Who Is" request registered information about different Domains (from NIC in the Internet).
Thus, there are many tools in Networks for locating and classifying Electronic Resources. All deal with using user-provided information regarding the subject matter, owner or electronic location of an Electronic Resource in order to identify its electronic address (URL in the Internet). Other tools attempt to create, update or extend such classification systems automatically by continually searching the Network's Electronic Resource space. Still other tools construct and retain user-classified lists of these addresses for later use.